We analysed the charts of 131 consecutive cases of spontaneous subarachnoid hemorrhage--without arteriovenous malformations--for seizures. Convulsions occurred in 31 patients (24%) and most often within 24 hours of bleeding. Motor manifestations of partial seizures were of no lateralizing value to aneurysm site. Early mortality, rebleeding and intracerebral hematoma were similar in both seizure and non-seizure groups. Late seizures were infrequent in survivors who had suffered seizures in the acute stage--thus questioning the necessity for routine, long term prophylactic anticonvulsants in these patients.